I am rather confident in my skills as a mechanic, I've been in the trade for more than a decade. So when the dealer told me my mysterious and sudden coolant consumption was due to a sleeve that had cracked and allowed coolant to be burned...I was skeptical.

So because I was skeptical I demanded to see the sleeve before they reassemble my engine. It was in fantastic shape and magnafluxing revealed no cracks, nor did a dye treatment. We found nothing at our shop. Fine, whatever, GM insisted it was the problem, they put the car back together last week and gave it back to me in short order. This was NOT a problem with my dealership, let me explain to you guys who don't know this but warranty stuff on powertrain components involves a process that is rather dull, long and arduous for the mechanic, it trades labor time for cost savings in parts.

Anyways, so last week, I'm coming home from work and someone flags me down, I am spewing white and blue smoke. This time roadside assistance came to get the car. They did not find anything mechanically wrong, gave the car back explained it as possibly left overs from putting it back together in the manifold or the turbo...yea right. This was NOT my normal dealership.

So I drove it to my usual dealership (props again to Southern Chevrolet) whom took the car and gave me a rental before they diagnosed it, since it was OBVIOUSLY mechanical. They inspected it the next morning, both my head, the same sleeve and the turbocharger had bit the dust, they stated it was likely a problem they hadn't found the first time following the diagnostics...duh, I already knew this but hey can't win them all.

So what had happened to cause all this? A piece of casting slag found in my downpipe directly in front of the cat leads everyone to guess it was stuck inside either the intake manifold or in the runners of the head. This piece made it through the engine, bent the exhaust valve on the #3 cylinder, got stock somewhere in the exhaust manifold and came loose again where the turbo inhaled it and came apart all at once. The turbo's impeller is intact but totally mangled which certainly suggests the piece of aluminum to have come from the head (aluminum normally melts at such a low temp it would have blown through the cat and we wouldn't have found it) the aluminum on has a higher melt point, so that would explain how we found it mangled but intact.

I am sorry I did not take pictures, the thought never occurred to me the piece looks like mangled casting slag and is about the size of a quarter. It also explains ALOT of my cylinder #3 misfires during tuning. The engine is in and I will get the car back Monday afternoon, they've been very quick, unfortunately I cannot take pictures of the old engine they require it be shipped back to GM for analysis. No my tune did not cause this, it's way too hot here to run tuned and I haven't had a tune on it since April.

Oh and they found the piece by chance, he was removing the engine, his words mind you and told me the pipe rattled like it had change in it, and just like that he found it.

And I went with a ClutchMasters kevlar clutch, the box says 70% hold over stock, I don't really care, I just figure with 23K, and the potential to make alot of power the clutch will need upgrading anyways.


Anyways, knock on wood we had our first rain AND oil shower today here in Louisiana, my car was indoors for it, YAY.

 

Thats pretty awesome

 

I think so too, if they haven't shipped off the old engine yet I swear I'll try and get pics of where the piece came from. I wish I could have kept the head, even with a bent valve I could have P&P'd it. The engine was replaced because they had already taken it apart once, the problem was not resolved, and the flow chart says to replace it at this stage. I may still do a P&P on the head of the new motor.

 

thats a bitch so ur under warrenty.. or noo

 

Last week my engine bit the dust with 24,5xx miles (09 ss/tc)...

https://www.cobaltss.net/forums/general-cobalt-68/09-ss-tc-new-engine-%40-24-xxx-miles-219564/

 

Under warranty or believe me I would have given the dealer the car for keeps. I didn't realize GM had gotten so difficult to live with. I'll be getting her back today, right back to break in procedures...

The engine itself barring the problem looked really good, the other three cylinders had perfect cross hatching there was little to no carbon deposits. the rings looked excellent and the rod cap pulled on #3 the bearings looked factory installed brand new and the plastigage proved it.

Anyways that's two strikes towards a lemon law...twice for the same problem, if it isn't resolved with this engine replacement (it will be) then GMAC has to buy back the car. For that reason they were big on making sure it would be fixed.

edit: Does anyone know the laws regarding factory warranty and engine replacement? Shouldn't the replaced part reset the warranty JUST for that part? It's not a huge concern I have the 100K extended warranty to keep me going and damn glad I got it.

 

Sounds like a familiar story..only I grenaded my turbo at Laguna Seca with a piece of the exhaust valve that probably stuck (melted) in the exhuast then let go a month later(after the head was rebulit!) at Laguna killing the turbo. The car went limp on the track at Willow Springs a month earlier and must have detonated...causing the spark plug to break up and that killed the valve (punching a whole in it).
I suspect your car detonated big time on the tune(?) and started the problem? You don't see these types of things *happen* on stock set ups vey often.

 

I'd agree with you, but my plugs looked good, I haven't been tuned since around late March, mostly because the heat has been pretty rough here. The dealer thinks it was casting slag in the intake tract that caused this since they didn't catch it on the first uncorking of the motor. No evidence of detonation to any component, no scorching, nothing to indicate any foul play on the face of the piston or a bad plug, everything seemed good when it went back together.


I also want to say that this motor seems tighter than the original (even when it was new). It is obviously a little snappier with throttle opening and seems to pull better in the driving range of 1800-2500 than the original did...I am not complaining. The part number for the new engine is not the same as the original and it did require a software update, it also required the replacement of a few sensors, that is what is on the work order. The new clutch is tight, comes in faster and really makes NLS well...scary, seems like it's a bit much and is tearing up my mounts. Anyone with an aftermarket clutch note some wicked NLS?

 

not changine the subject bud but glad to see another ss/tc member close to me, im in ponchatoula LA and in the baton rouge area...but anyways sorry to hear about all the problems i'd freak if that happened to mine

 

Hey bro, likewise, I'd be down for a cruise sometime if we could get a third and maybe a fourth wheel in on it. Id say ride the beach roads south of Lafeyette but...yanno. Could ride out on a Saturday morning to State Capital Raceway or if I've got the money No Problem.

 

I believe when I had an engine replacement done, they reset the warranty on the motor itself.

 

Oh I forgot to add, the original engine is long gone, GM pays back dealerships for big items like that so it was gone the day after it came out.